EGCJFlyer,
Believe me, I don't want to put anyone off flying. And I don't think anyone else here does either. But...
You say this is your first long trip. Have you flown for an long as eight hours before, in unfamiliar territory, over such a short period of time? Have you taken up three non-flying friends before? Have these particular friends been in a light aircraft for such long periods before?
I ask all this because fatigue and stress are strange things. As someone mentioned, looking after non-flying passengers can be tiring. And long flights, doing all the radio and nav, and particularly all the decision making yourself, is also exhausting. You don't notice it at the time; that sort of fatigue is quite insidious. But you can start to make mistakes, or just not be quite ready to cope if things don't quite go according to plan. If you get overloaded (mentally I mean; not talking about the aircraft here), there is no-one to help out, or to recognise that you're overloaded. And you won't recognise it; there just isn't enough of your overworked brain left to stand back and say: "OK, you're overloaded; orbit and chill out".
At your stage, I certainly shouldn't have been doing long flights like this one, with three passengers, to an area of the country with a lot of inhospitable terrain and known for its sudden weather changes. I'm not saying that means that you shouldn't do it; I don't know you, so I can't say that. But do YOU know it? Do you have enough experience to know that you can do this? If you haven't done so, maybe you should work upwards, from something a little less challenging - less passengers or somewhere closer to home or an easier place to land. I don't know if you're over-confident, but I do know that over-confidence is common among low hours pilots. You don't - and can't - know what you don't know.
Unless there are some facts here that you haven't told us, I really think you should take less passengers or go somewhere else. Feel free to think I'm a worrying wimp if you like. But you did ask!